1. Field of the Invention
The present invention relates to a vacuum surge protector for the aspiration line of an interocular surgical system.
2. Description of Related Art
Human tissue is sometimes emulsified with an ultrasonic instrument. For example, cataracteous lenses are typically removed with an ultrasonic tip that is inserted into the cornea of the patient. The vibrating tip emulsifies the lens into small particles that are removed by an irrigation/aspiration system coupled to the ultrasonic instrument. A conventional interocular fluid system includes an irrigation line that is connected to a gravity bottle which supplies an irrigation fluid to the tip of the instrument. The fluid system also contains an aspiration line that is attached to an inner channel of the ultrasonic tip. The aspiration line is typically connected to a vacuum pump which draws the fluid and lens particles away from the surgical site.
Some of the lens particles may become occluded within the aspiration line and interrupt the flow of fluid from the eye. An occlusion of the aspiration line will create an increase in the vacuum pressure downstream from the point of blockage. Likewise, the gravity bottle will create an increase in the fluid pressure upstream from the occlusion. The pressure differential across the aspiration line will cause a corresponding surge in the flow of fluid from the eye if the occlusion becomes dislodged. The pressure surge can cause the cornea to collapse and damage the eye.
U.S. Pat. Nos. 5,106,367 and 5,167,620 issued to Ureche et al. disclose a surge suppresser for an interocular surgical system. The Ureche surge suppresser is a tube which has a wall that is thinner than the wall of the aspiration line. When an occlusion occurs, the tube wall collapses and increases the fluid resistance within the aspiration line. When the occlusion dislodges, the collapsed wall prevents any sudden surge in the flow of fluid from the eye. Although effective in preventing vacuum surges in the system, the Ureche tube is susceptible to occlusions within the tube itself.